1. Field of the Invention
The present invention relates to a surface modifier for imparting properties characteristic of fluorocarbons to the surface of inorganic materials.
2. Discussion of the Background
Among known fluorine-containing surfactants or surface modifiers are fluorine-containing compounds, including those which contain a hydrophobic group of a long fluorocarbon chain and a hydrophilic group, such as --SO.sub.3 H and --CO.sub.2 H, or, in place of such a hydrophilic group, a hydrocarbon chain. Such fluorine-containing surfactants or surface modifiers (1) are capable of lowering the surface tension of water to a considerable degree, (2) exhibit a high surface activity at a low concentration, (3) are excellent in heat and chemical resistance, (4) can exhibit surface activities in organic solvents and (5) possess both water and oil repellency, and hence they can be superior to prior hydrocarbon surfactants or surface modifiers. However, they are poor in their bonding power to the surface of inorganic materials. It is also known that hydrocarbon chain-containing aluminum compounds can be useful as surface modifiers since the compounds can be bonded, by means of a covalent bond, to the surface of inorganic materials, thus imparting thereto such properties as water and oil repellency. It is, however, difficult to disperse fillers treated with such a fluorinated carbon chain-containing aluminum compound into a fluororesin or to use such a compound as a primer for fluorine-containing paints. The reason for this can be attributed to the fact that the SP values of fluororesins and fluorine-containing paints are low. Although fluororesins have excellent properties characteristic of fluorine compounds, such as excellent chemical resistance, heat resistance and electrical properties, the resins suffer from the disadvantages that their price is high, and they are poor in molding property, coloring property and processability upon filling of inorganic fillers. Fluorine-containing paints are disadvantageous in that they are poor in coloring property, which is basic for paints. Because of their low surface energy, fluorine-containing paints are also poor in adhesive powder to materials to be painted and hence require the use of an excellent primer.
Japanese Patent Applications (Laid Open) Nos. 254,119/85 and 297,478/86 describe fluorinated carbon chain-containing couplers, in particular, titanate couplers. However, it is also known that aluminate couplers are more effective than such titanate couplers, as far as effects for certain kinds of fillers, such as carbon black or the like.